Stitch-forming mechanism for sewing machines



March 26, 19 29. cf |u EL STITCH FORMING MECHANISM FOR SEWING MACHINES 5 Sheets-Sheet Filed Jan. 29. 1927 Marh 26, 1929. c, F, RUBEL 1,707,068

STITCg F6RMING MECHANISM FOR SEWING MACHINES Filed Jan. 29, 1927 5 Sheets-Sheet Z March 26, 1929. I c. F. RUB EL' 5 S TITQH FORMING MECHANISM FOR SEWING MACHINES Filed Jan. 29, 1927 s Sheets-Sheet 5 March 26, 1929. .c: F. RUBEL STITCH FORMING MECHANISM FOR SEWING MACHINES Filed Jan. 29, 192*? s Sheets-Sheet 4 March 26, 1929. .c. FJRU BEL 1,707,068

STITCH FORMING MECHANISM FOR SEWING MACHINES Filed Jan. 29, 1927 5 Sheets-Sheet {1m 66 ea E Patented Mar. 26, 1929.

UNITED STATES PA or-Fi es.

oz-ianiins r. RUBEL, on CHICAGO, .rnnnvorsnssionoa :ro UNION SPECIAL-MACHINE company, on CHICAGO, ILLINOIS, A CORPORATION or rumors.

STITCH- FORMING LIECHANISM FORSEWING MACHINES.

Application filed January 29,1927. Serial No. 164,508.

The invention relates to new and useful improvements institch forming mechanism Lil for sewing machines, and more particularly to a thread laying mechanism for a multiple needle covering stitch forming mechanism. An object of the invention is to provide a covering thread laying mechanism for a multiple needle machine having one needle point set higherthan anotherneedlepoint,

wherein the needle with the lowest set point cooperates with the covering thread laylng mechanism in the positioning of the cvering thread so as to be secured to the fabric by the needlethread loops. 7

Another object of the invention is to provide a thread laying mechanism wherein the covering threadislaid in loop formfthrough the aid of a: movable thread guide and a cooperating thread hook, wherein said hook and guide are so positioned and timedas to carry the covering thread against one of said needles, and in rear ofa nother ofsaid needles, said needles being set at different heights to permit the covering thread to be laid as stated.

guide are oscillated by a single vertical shaft, and wherein the vertical shaft is oscillated by a horizontal shaft receiving its oscillations from the main shaft.

A still further object ofthe invention 1s to provide a covering thread laying mechanism of the above type, wherein the thread hook is mounted to oscillate abouts vertical axis located in rear of the vertical axis of th thread guide.

These and other objects will in part be obvious and will in part be hereinafter more fully disciosed. i In the drawings which show by way of illustration one embodiment of the invention Figure 1 is a frontview showing a portion of the machine embodying my improvement; Fig. 2 is a view showing in end view, the mechanism at the free end of the overhanging arm, and in side view, a portion of the work supporting arm;

Fig. 3 is a viewpartly in' sectionfland partly in elevation from the "rear of the machine;

I Fig.4 is a detail showing the stitchformmg mechanism as viewed from in front of -the"needles;

Fig. 5 is 'a perspective view of the thread "laying mechanism, also showing one ofthe supporting brackets detached;

of Fig.2;

Fig. 7 is of Fig.2;

Fig. 8 is a view similar to Fig. 7, with the thread*hook'and thread guide moved to the other ends of their strokes; Fig. 9is a detail showing'the arrangement of the needlesythe threadguide andthe thread hook,and diagrammatically, the seam formed thereby; V i i Fig. -10is a diagrammatic enlarged plan view oi. these'amfand Fig. ll is a diagrammatic View showing the needles, the matcrialfthe covering thread guide, and the covering thread hook at the time when 'the strand of the loop in t-hecovsectional View on the lineG, 6

a sectional View on the line 7, 7

ering thread is laid against one of the needles.

The invention is directed broadly toa covering'thread laying mechanism for a sewinginachincw Ihe machine includes a plurality of needles, preferably three, a single loopcr which cooperates with theneedles bene'ath the work support, and a covering thread laying mechanism which cooperates with thefneedles above the work support. The needlepoint-s are setatdifferent heights, with the needle, the 100501? which is first entered bjy'a. loopcr, set the highest. The machine may be further provided with a trimming mechanism, if the machine is used for operating 'upon knitgoods, so that the edges of the fabrics being joined and covcred, may be trimmed. The machine may also be provldedwith means for lappingthe fabric sections after they are trimmed and prior to the stitching thereof, the lapping of the sections 'being within the limits of the covering stitches. The invention is directed particularly to this covering thread laying mechanism which includes an oscil lating hook and an oscillating thread guide mounted to oscillate about independent vertical axes. 'The thread hook and thread guide are sopositioned-andtimed, that the the thread guide also moves to the inner end ofits stroke, and the thread between the eye and the hook is carried against the needle having the lowermost point, engaging said needle somewhere in the region of the eye.

The covering thread may also be carried against the middle needle, if three needles are used, depending upon whether the needle is set sufiiciently low to be engaged by a covering thread, or sufiiciently high, so that the covering thread will. pass beneath the same. The needle with the highestset point is set sufliciently high so that this strand of the covering thread loop between the hook and the thread guide is carried in rear of said needle. This-forms a loop in the covering thread. which. is entered by the needle point which is lowest set, and also by the middle needle, if the point is set sufliciently low as to be engaged by the said strand of'covering thread. The thread hook and thread guide for the covering thread are both; oscillated by. a vertical shaft which carries arms projecting in opposite ,directions, and onearm is connected to the ;hook,; while. the other is connected to the thread guide' The respective connections between these arms, and the vhook and the guide are such that the hook and guide will 1 be. moved in opposite direct-ions; that is,

toward each other or away from each other upon an oscillation of the vertical actuating shaft therefor; This vertical actuating shaft may be operatediin any suitable way,

depending upon the character or,type of machine in which the improved covering thread laying mechanism is employed.

- Referring more in detail to the drawings,

, I have shown my improved covering thread layingw mechanism as applied to a teed-oil":- the-arm-machine designed particularly for stitching tubular. work. I have also shown this. type of machine as equipped with a. trimming mechanism and a difl'crential feed for operating upon knit goods. It is to be understood, however, that the invention mayv be used in other. types of machines; as for example, a flat bed machine, and it is also adapted to be used tor forming covering stitches inv woven materials as well as in knit ,materials, and when used In connection with woven materials, a single feed may be used,

I and the trimming mechanisms dispensed with."

. ,I; will-now describe the present embodiinent 'of the invention which consists in a work su iporting arm 1 which is cylindrical in 'form, and the material to be stitched is placed around the'arm, the edges of the ma- 7 vterialbrought to a meeting line and overilappedfif desired, and then fed ofl from the end of thearmc Located in' this work "supporting arm is a feeding mechanism,

which includes a main feed dog 2, and a differential feed dog 3. Also located in this work supporting arm is a thread carrying looper 4;. These parts are of the usual construction, and ham only been indicated in a very diagrammatic way. The material is held on the work support by a prcsser foot 5, carried by a presser bar (5. This presser bar 6 is mounted in the free end of an overhanging arm 7. The overhanging arm is carried by a standard 8 in which is located the main operating shaft 9 (see Fig. 3). Also mounted in the overhanging arm 7 is a needle bar 10, which is i'eciprocated by a needle lever 11 actuated from the main shaft 9. The needle bar 10 carries three needles 12, 13 and 14-. The needle 12 is set so that'its point is considerably lower than the point of the needle 14, while the central needle 13 is set with its point higher than the point of the needle 12 and lower than the point, of the needle 14. This setting of the needle points, one higher than the other, is the usual form or arrangement of the needles where there are a plurality of needles, and a single looper cooperating'with all of the needles The presscr foot is provided with a slot 15 leading into the forward end thereof, and a V-shapcd rib 16 carried by the work supporting arm cooperates with the slot in directing the edges which are to be joined by the stitching mechanism in an upturned position, so that the edges may be trimmed before they are covered by the stitches. The machine is provided with a trimming mechanism including a stationary trimming blade 17 and a movable trimming blade 18. The movable trimming blade moves across this slot in the presser foot and trims the upturned edge portions of the fabric sections, after which the prcsscr foot is provided with means for turning said trimmed edge portions down into overlapped relation. In Fig. 10 of the drawings, I have shown one of the fabric sections at F, and the other at F. The presser foot is provided with a needle opening 19 through which the three. needles pass.

The movable trimming blade 18 is carried by an arm 20, which in turn. is carried by a yoke 21 mounted to oscillate about the presser bar (3. The upper end of the yoke is engaged by a spring 21' which bears against a collar 22 fixed to the prcsser bar 6, and this spring yicldingly holds the mmableblade in shearing relation to the stationary blade. The yoke is provided with an arm 23 which is connected by means of a link 24 to a crank 25 on a shaft 26 journaled in bearings 27 and 28 at, the rear of the machine. This shaft 26 is provided with an arm 29, and a link 30 attached to the arm 29 cooperates with an eccentric member 31 on the main shaft 9. Thus it is that the shaft 26 is oscillated, and when said shaft lllO center of the shaft 39.

is oscillated, willoscillatc the yoke czrr mg the movable trlmmingblade, and this will cause said blade to trim tl1e ed repor- 'tions of the fabric sections.

3st has a depending sleeve portion 35, and

the thread guide 32 is provided with a vert1cal shank 36 wlnchis secured 111 said sleeve portion by set screws 37, 37. The 'lever arm 34 is secured by a vertical pivot bolt 38 to a bracket 38, which in turn secured to the overhanging arm byscrews 38 38". Mounted in suitable hearings in the overhanging arm and at the rear side of the needle head, is a vertical shaft 39. This vertical shaft is held from endwise movement in said overhanging arm by collars 40 and (ll which are fixed to the vertical sl: ft 39. The pressor foot is provided with a rearwardly extending arm 42 carrying a sleeve 43 which surrounds the lower end oflhe shaft 39, and freely moves up and down thereon when the presser foot raised and lowered. This vertical shaft 39 is provided with. an armed carrying aball stud and a link 45 c0- .operating with said ball stud is connected to the cranl :25on the shaft 26.

The shaft 39 is also provided with an arm 46. A link 47 is pivotally connected to the outer end of the arm 46, and. this link 47 is connected at 48 to the lever arm 34 which carries the thread guide 32. i V

The thread hook 33 is mounted in alever arm 49. Said lever arm 49 has a depending sleeve 50, and the hook has a vertical shank portion 51 engaging said sleeveand secured therein by screws 52. This lever arm 4-9 is secured to the bracket 38. Said bracket has an arm 53 extending rearwardly from the bracket 38, and a pivot bolt 54 passes through an opening in the lever arm 49 and is threaded into an opening in the outer end of the arm 53. The bracket 38 has a forwardly projecting arm 56 which is provided with an opening into which the pivot bolt 38 is threaded. The vertical shaft 39 is provided with a second arm 57 which is in alinement with the arm 46, but projects in an opposite direction from the A link 58 is pivoted to the outer end of the arm 57,:1ud pivoted at 59 to the lever arm 19 which carries the thread hook.

From the above it will be obvious that when the shaft 39 is oscillated, it will oscillate the thread hook 33 through the link connection 58, an will also oscillate the thread guide 32 through the link connection 47. The link 47 is connected to the lever arm at at a point intermediate the pivotal point of the lever arma'nd the thread-guide, while are descending.

the link 58 is connected to the lever arm 49 atone end thereof, and thepivot pointof saidleverarm 49 isbetween this connection tothe linkand the hook. Asa result, when the vertical shaft is oscillated in one'direction, the hook will be moved one way and the thread guide will be moved the other way. That is, the thread hook and thread guide will be-movcd toward each other, and

whenthe shaft is oscillated in the other direction, then the thread hook and thread guide will be moved away from each other.

The covering thread is indicated in the drawings at c. The covering thread is led from the supply through suitable guides, and

finally to the stationary thread guide 60 carried by the presser foot. The covering thread then passes through a thread guide 61 on the shankof the thread guide, and to the thread guide32. Thethread guide and thread hook are disposd a sufiicient distance above the presser foot as to permit the presser footto be raised and lowered. Said thread guide and thread'hook oscillate in fixed planes relative to the needle head on the overhanging arm. The thread of the needle 12 indicated at a; the thread of thencedle 13is indicated at n, andtheth read of the needle 14 is indicated at a The thread guide oscillates from an outer position, asshown" in Fig. 7, to an inner position, as shown in Fig. 8. Atthe same time, the

thread hook moves from the outer position,

shown in -7, totheinner position, shown in Fig. -8. As the thread guide and thread hook move to their inner position, the needles are at the upper ends of their strokes, and The thread guide 32 is so pivoted onv its supporting bracket 38" that the path of movement of the thread'guide from in front of the needles to a position slightly in rear of a vertical plane containing the center of the needles. The thread hook swings in a longer are, as the pivotal support for the thread hook is in rear of the pivotalsupport for the thread guide. The thread hook fnovesin apath, therefore, from in front of the needles to a point substantially terminating in a vertical plane containing the center of the needles. As the thread hook moves to the inner end of its stroke. it engages the covering thread 0, passing through the thread guide 32 between the thread guide and where the covering thread is interlocked with the stitching. threads at the previous stitch. The thread hook, there fore, forms loop indicated at c in Fig. 9 of the drawings. The strand running between the hook and the thread guide is carried against the needles 12 and 13. As clearly shown in Fig. 4: of the drawings, the needles at this time are at such a position in their path of reciprocation, thatthe points of the needles l2 and 13 are below the covering thread,'while the point of the needle 14 lOtJ llO

iswell above the covering thread. This is clearly shown in Flg. 11 of the drawings.

i Aswill be clear from Fig. 9 of the drawings,

the'strandof the loop extending between the .hook and the thread guide, and which engages the needles 12 and 1 3, willbe positively held infront of said needles by the needles themselves, while this same strand of the thread loop .0 is carried in r 0f the needle 14. Thus it is that the two needles 12 and 13 enter the thread loop a while the covering thread is laid around the in such a way relative to the needles, as they descend,that certain of the needles will enter the covering thread loop, while the other needle or needles Wlll. anchor the covering 7 thread to the fabric. By this arrangement, I am able to lay the covering thread in loop form, for each reciprocation of the needles,

and thus fully cover the raw edge of the fabric.

It willreadily be seen that if the point ofthe needle 13 is raised slightly, even though 1t is not set as high as the point of in rear of this needle 13.

the needle 14, the covering thread 0 will pass It is essential that the covering thread shallalways be in front ofthe needle 12, and always be in rear of theneedle 1 1. The position of the covering thread relative to the central needle or.

needles is immaterial. I

From the above it will be apparent that I have provided a covering thread laying .n'iechanism for a sewing machine having a plurality of needles set abreast, which 13 7 very simple in "constructim and wherein *the cooperating covering thread guide and loop forming hook are moved toward each other and away from each other by a single actuating shaft, and wherein the needles are ,soset, and the hook and guide areso pesi tioned' and timed, that. the strand in the covering thread loop which is anchored to thepr'eviously formed stitches, is laid in rear of the path of the needles, \VllllO the strand extendlng between the hook and the guide for the covering thread is laid against the needlenearest the hook, and the strand thereby deflected in its course between the hookjand the guide so that said strand is laidiwith certainty in rear of the path of the needle nearest the guide.

\Vhile Thave shown my improved covering thread layingmechanism as embodied a machine for forming tubular articles, from knit material, it will be understood, as

has already been noted, that the covering thread laying mechanism may be used in other types of machines without departing from the spirit of the invention as forth in the appended claims.

Having thus described the invention, what I claim as new and desire to secure by Letters-Patent, is

1. The combination of a plurality of needles; of a covering thread laying mechanism cooperating therewith and including an oscillating covering thread guide and an oscillating hook, a lever arm fulcrumed at its end carrying said guide, a lever arm fulcrumed intermediate its ends and. carr ing said hook, a vertically arranged actuating shaft, arms projecting in opposite directions therefrom, a link connecting one of said arms with the end of the lever arm carrying the hook, and a link connccl-ing the other arm with the lever arm carrying the guide intermediate the fulcrum therefor and the guide, and means for actuating said vertical shaft.

2. The combination of a plurality of needles; of a covering thread laying mechanism cooperating therewith and including an. oscillating covering thread nide and an oscillating hook, a lever arm fulcrumed at its end carrying said guide, a lever arm fulcrumed intermediate its ends and carrying said hook, a vertically arranged actuating shaft, arms projecting in opposite directions therefrom, a link connecting one of said arms with the end of the lever arm carrying the hook, a link connecting the other arm with the lever arm carrying the guide intermediate the fulcrum therefor, and the guide, and means for actuating said vertical shaft, said last-named means ineluding a horizontally disposed shaft, a crank arm carried theirby, an arm on the vertical shaft, and a link connecting said lastananied arm to the crank arm on the horizontal shaft.

3. The combination with three nccdlcs set abreast and having the point of the needle at one side of the scam lower than the point of the needle at the other side of the scam, of a covering thread laying mechanism including devices positioned and timed for forming a loop in a covering thread and placing the strand of said loop running to the supply against the side face of the needle \vitlrthe lowest set point and subsequently placing said strand running to the supply beneath the point of the needle at the other side of the same and in rear of the path thereof, whereby the needle with the lowest set point enters the loop formed in the covering thread and the covering thread is anchored to the fabric preparatory to the forming of another loop therein.

1. The combination with three needles set abreast and having the point of the needle at one side of the scam lower than the point of the needle at the other side of the seam, of a covering thread laying mechanism in cluding a covering thread guide oscillating from a position at one side of said needles to a position at the other side thereof and in a path in front of the needles, a hook cooperating with the guide and oscillating from one side of said needles to the other side thereof and in a path in front of said needles said needles being set so that the point of the needles nearest the hook when the loop is formed is lower than the point of the needle nearest the thread guide at this time, said guide and hook being so positioned and timed that a loop is formed in the covering thread and the strand running troin the hook to the guide placed against the side face of the needle with the lowest set point and subsequently moved beneath the point and in. rear of the path of the needle with the highest set point, whereby the needle with the lowest set point enters the loop formed in the covering thread and the covering thread is anchored to the fabric preparatory to the forming of another loop therein.

In testimony whereof, I afiix my signature.

CHARLES F. RUBEL. 

